The device hasn’t been released yet but a way to root the International variant of it (SM-G900F) has already been achieved. The credit for it goes to XDA Senior Recognized Developer Chainfire whose CF-Auto-Root tool roots the device and installs the SuperSu app on it. Follow the below mentioned steps to easily root your Galaxy S5. Do note however that the method has been tested to work only for the SM-G900F variant, so do not try this on any other model as it may brick your device.